Jim Strachan tried to be smart when shopping for a new air conditioning system for his 1,400-square-foot Westworth Village home. Burned before by an AC company, he carefully picked a name he knew -- Sears Home Improvement -- which advertises in its mailings: "Trust Sears to deliver superior service and craftsmanship."

Big-box stores that offer home improvement services don't send guys from the store to do the work. Sears, Lowe's, Home Depot and others hire outside contractors to take these jobs. Sears hired ACAR Air Conditioning & Heating of Dallas.

How did things go?

By the time this escapade ended 18 months later, there were three different units installed, Strachan sued Sears, and Sears and ACAR found themselves in deep trouble with state regulators. A state inspector found a number of rules broken in the process of trying to cool Strachan's house down.

Strachan burns when he describes what happened. His business, which operated out of his home, shut down. He's lost thousands of dollars. Even his cat died, he says, from the heat.

The Watchdog found one easy way to prevent this, or at least minimize the chances of such a system failure. But first here's what happened.

In January 2011, Strachan agreed to pay Sears $7,500 for a 3-ton unit. Two months later, Strachan complained that the house wasn't cooling. Sears told ACAR to replace it with a 4-ton unit.

Even with a bigger unit, Strachan says that during the hot summer of '11 his little house wouldn't drop below 85 degrees. ACAR techs kept working, but they couldn't fix it.

After Strachan complained to the Texas Department of Licensing and Regulation, a state inspector "found multiple installation defects."

In December, Strachan sued Sears Home Improvement in Tarrant County civil court under the Deceptive Trade Practices Act. His lawyer, Markus Kypreos, asked for triple damages.

The lawsuit was settled this summer for an undisclosed amount, but it's not over. The state sent violation letters to both Sears and ACAR.

Sears was ordered to pay a $15,000 fine. But if Sears contests the fine, it jumps to $20,000.

Sears requested a hearing, but the state won't grant it, he said. Because of that, Sears has given Licensing & Regulation's staff lawyer "a short deadline to withdraw or dismiss the false charges, or otherwise Sears will have no choice but to bring this attorney misconduct to the attention of the disciplinary authorities of the Texas State Bar." That's hardball.

In its defense, Sears points out the installation passed a Westworth Village inspection. Sears declined to answer further questions. State regulators decline to comment because the case is pending.

The state threatened ACAR with a $10,000 fine, with a jump to $14,000 if contested, ACAR President Alex Castelan said in an interview.

Castelan acknowledged that he didn't get a city permit for the second unit until three months after the installation because he thought Sears was going to do it. He blames the customer for being difficult: "Regardless of what you did, he was never happy with anything."

A former AC tech for Sears before he started his own company, Castelan worked the last six years as an outside licensed contractor handling jobs for Sears Home Improvement. He no longer works with Sears and calls their breakup "kind of a messy deal." He says the state's allegations are unfair.

At least Strachan's system now works. He hired Harmony Environmental Air Conditioning & Heating. Owner Jesse Williams explains, "The air was getting cool but the system wasn't removing the humidity. So it felt like a jungle in there."

He downsized the system to a 3.5-ton unit, readjusted the duct work and made other changes.

How to avoid this? Hiring AC techs in Texas is risky business. For every great company, there's one that isn't.

In Texas, company owners like Castelan should be licensed as AC contractors. (He is.) But what about the techs a contractor hires?

Techs don't get licensed, but they have an option to become a "registered technician." There's no educational requirement for that. A higher level is called "certified registered technician." To get that, a tech must pass an exam. That shows diligence.

Castelan told me his two techs at Strachan's house are registered. I checked the state website; they're not.

My suggestion: when hiring an AC company, make sure the company owner carries a state license. Then make sure the techs are registered, or better, certified and registered.

Don't trust their word. Check with state Licensing & Regulation by phone or by website.